Background: The active involvement of learners as critical, reflective and capable agents in the learning process is a core aim in contemporary education policy in Australia, and is regarded as a significant factor for academic success. However, within the relevant literature, the issue of positioning students as agents in the learning process has not been fully examined and needs further exploration. Purpose: This study aims to explore ways in which aspects of self-regulated learning theory may be integrated with the concept of agentic engagement into classroom practice. Specifically, the study seeks to scaffold students' self-assessment capabilities and self-efficacy by using a formative assessment-as-learning process. The research examines how scaffolded planning, as part of the forethought phase in the Assessment as Learning (AaL) process, influences self-regulation and student agency in the learning process. Sample: 126 students from school years two, four and six (student age groups 7, 9 and 11 years), and 7 teachers at an independent (coeducational, non-religious) primary school in the Northern Territory, Australia, participated in the study. Design and methods: Conducted as a one-setting, cross-sectional practitioner research study, the data sources included students' planning templates, writing samples, interviews with students and teachers and email correspondence with teachers. The data were analysed for emerging themes and interpreted from a framework of social cognitive theory. Findings: In this study, students were given the opportunity and support to exercise agentic engagement. Findings suggested that, in particular, students who were identified by their teachers as low-achieving and/or with poor motivation, were perceived by the teachers as exceeding expectations by demonstrating relatively greater motivation, persistence, effort and pride in their work than would be the case usually. Conclusions: The findings from this formative AaL study suggest that AaL has the potential to help scaffold primary students' development of assessment capabilities.